Pilot flame control for



Patented May 30, 1950 rinor FLAME CONTROL Foa FUEL commas Woods StocktonWalker, Great Neck, N. Y., as-

signor to Consolidated Edison Company of New York, Inc., New York, N.Y., a corporation of New York Application April 10, 1946, Serial No.661,028 3 Claims. (Cl. 158-117.1)

This invention relates to apparatus for controlling a pilot flame of afuel burner, and more particularly to pilot flame control means for agas furnace.

Heating apparatus such as those employed for heating houses, for exampleof the gas burning variety, usually are provided with a master gascontrol valve on the gas supply main for the purpose of shutting oil thegas supply when the use of the furnace is to be discontinued for anappreciable period, such as the summer season. The closing of such avalve, in some types of heating apparatus heretofore employed, shuts offthe supply of gas not only to a main burner of the furnace but also to apilot flame in the furnace. Certain other types of heating apparatusheretofore used have been provided with a separate pilot ,valve controlwhich is not affected by the opening or closing of the master valvebecause the pilot gas conduit is connected, for example. upstreamrelative to the master valve.

It is desirable that the users of such apparatus themselves shall beableto turn on and off their furnaces. This involves no substantialdiiilculties with regard to the turning oil. of the fuel. However, withrespect to turning the fuel on again, diiflculties arise with largenumbers of users because of their reluctance or inability to light thepilot flame. In fact, it has been found to be true, especially in largemetropolitan areas. that the average furnace user not only requests andexpects the fuel or gas company to turn on his fuel whenever it is sodesired, but also to turn it off. Thus, in the spring and again in thefall large numbers of furnace users make heavy demands upon fuelcompanies for such services.

It has been necessary in the past for companies providing fuel, such asgas or oil, to maintain service staffs which devote their time to theturning off and on of the fuel, and to the extinguishing and igniting ofpilot flames in furnaces, especially in the spring and fall.

Ihe maintenance of staffs for the above purposes constitutes an addedexpense which must be passed on to the users of the furnaces. Inaddition to the expense of this method for starting and discontinuingthe operation of furnaces, there is usually the inconvenience of delaybetween the time a request is made for this service and the time ofcompliance.

In heating apparatus heretofore employed a disadvantage has existed inthat during periods of non-operation of the furnace, such as the summer,the pilot flame is totally extinguished. The temperature within thefurnace thus often falls below the dew point and a strong tendencyarises for the metal surfaces of the furnace to rust or corrode. This isespecially true in damp cellars where furnaces are often located.

Furthermore. apparatus heretofore employed for starting pilot flameshave been expensive to manufacture and maintain.

According to the present invention, apparatus is provided forcontrolling a pilot flame for a furnace which will eliminate the abovenoted diffleulties.

Various further and more specific objects, features and advantages ofthe invention will clearly appear from the detailed description givenbelow taken in connection with the accompanying drawing which forms apart of this specification and illustrates, by way of example, preferredarrangements of apparatus for carrying out the invention. The inventionconsists in such novel combinations of features and apparatus as may beshown and described in connection with the equipment herein disclosed.

In the drawings:

Fig. 1 is a schematic diagram of one form of apparatus for carrying outthe invention; and

Fig. 2 is a view partly in section and with parts broken away showing anovel embodiment of a pilot control valve and main fuel control valve.

Referring to the drawings in further detail, simple and inexpensivemeans are provided which enable a furnace user personally to turn on andoff his furnace comprising a main valve and a pilot flame control valve.The user by these means may easily turn down the pilot flame to a smalland economical size during extended periods when no heat is required,and he may personally turn the pilot flame to its full operating size atother times without aid from a fuel company or any servicing agency.

The average pilot flame for furnace burners may consume gas at a rate ofapproximately five cubic feet per hour when of full size. At this rate apilot flame, which burns during an average summer season, may consumeenough gas to involve substantial expense to the user. If the pilotflame is reduced to a point where it is as small as possible, and stillconstitutes a stable flame, the amount of gas consumed during an averagesummer season may be reduced by as much as two-thirds.

Generally, according to prior practice, during a summer season the pilotflame is turned oil entirely and the furnace is shut down, the cost formaintaining a full pilot flame being thereby avoided. However, in orderto provide the convenience of having heat whenever it is desired Iwithout the delay of waiting for a service agency.v

a reduced pilot flame may be maintained with the present invention at anominal cost, entirely acceptable to most furnace users.

In the embodiment shown in Fig. 1 means are provided for producing afull pilot flame during normal operation of a gas furnace, and forproviding a reduced or small pilot name when it is desired todiscontinue the operation of the furnace seasonally or at any othertime. The reduced pilot flame which burns continually constitutes themeans for lighting the full pilot flame.

A fuel burner, for example, of the gas burning type, of well-knowndesign is provided at IU having a burner element Ii which is incommunication by means of a conduit with a suitable source of fuel (notshown). A conventional main shut-oi! or primary control valve may beprovided at II. The latter is normally maintained in an open positionbut may be employed for shutting down the furnace.

A secondary fuel control valve, also of conventional design, may beprovided at H and is adapted' by means to be hereinafter described,intermittently to open and close in a. well-known manner in response,for example, to room temperature.

The secondary control valve I4 may be operatively connected in a knownmanner to, for example, two diflerent heat-responsive means. In theembodiment shown, valve I4 is connected to a room thermostat l5, and toa second thermostat which is variously termed as a furnace thermostat, apilot flame thermostat, or a safety thermostat. The latter mayconstitute, for example, a bi-metallic strip which opens or closes avaive control electric circuit l1, I8 in response to heat appliedthereto. Thermostat i6 is adapted to be actuated by a predeterminedminimum amount of heat. In a manner to appear hereinafter it is actuableby said full pilot flame but not by the reduced flame. Said circuit isconnected to a suitable source of electric energy (not shown) by meansof leads L1, L2. The above-mentioned operative connection between valvel4 and the thermostats I! and It may comprise the circuit l1, l8, and asolenoid I! in the circuit which, when energized, is capable of moving asuitable valve control arm 20 against the action of a spring 2| to openvalve H.

A pilot flame conduit or tube 22 is provided having a nozzle or burner23 which is preferably adjacent the furnace thermostat IS. The pilotflame tube is in communication with conduit l2 at a point 22' which isdisposed upstream relative to the valve 13.

' Novel means are provided for controlling said pilot flame, which meansare extremely simple of operation and are adapted for personal manualoperability by thefurnace user, whereby a, full flame may be producedand controlled during normal operation of the furnace, and a reducedpilot flame of economical size may be easily obtained and maintainedduring periods of seasonal nonuse of the furnace. In the form shown inFig. l,- the novel means comprise a pilot control valve 24, around whicha by-pass 25 is provided. Fluid flow through the latter preferably isadjustable, for example, by a suitable piston type valve capable of fineadjustment by angular movement of a threaded screw. Such adjusting meansmaybe located at 26. A small amount of fuel thus'may flow to the nozzle23 at all times even though the main pilot control valve 20 is closed.This small amount of m1 is suflicient to provide the reduced pilot flameabove discussed.

In operation, when the furnace is in normal use both main valve II andpilot valve 2. are in open positions. The pilot flame at 22 is at itsfull size. The heat from the full pilot flame is suflicient to actuatethe heat-responsive means It thereby closing at that point the electriccircuit II, It. The flow of fuel through conduit i2 thus is controllablein a well-known manner by the thermostat i i in cooperation with valvemeans H and the solenoid It. When it is desired to suspend the operationof the furnace for a considerable period, such as the summer season. thevalve I3 preferably first is closed. The pilot flame at 23 is still atits full size. Circuit il, II is. therefore, closed at the thermostat Iand valve I4 is operable in its usual manner by the thermostat it eventhough no gas may flow to the furnace.

The pilotcontrol valve 24 is next closed. The

main flow of fuel to the pilot flame consequentLv is shut off. However,a sufficient quantity of fuel flows via the by-pass 25 to maintain asmall but stable flame at the nozzle 22. The smallflame is not ofsufficient intensity to actuate heat-responsive means It. Consequently,the circuit II, II is promptly opened. During the period when only thesmall flame burns it is, therefore, impossible for the solenoid it to beenergized. Consequently the control arm 20 of valve I4 is withdrawn to aclosed position by the action of spring 2|, and the room thermostat IIis ineffective to control the furnace. During this period the heat fromthe reduced pilot flame is sufficient to maintain a temperature withinthe furnace in excess of the dew point and thus serious corrosion may beavoided.

When it is desired to put the furnace back in operation, for example, atthe end of the summer season, the above procedure is reversed. First.the pilot valve 24 is opened, thereby producing a full pilot flame, theintensity of which actuates the thermostat l6 and renders operable thevalve control solenoid I9 and the valve ll. Next, the

main valve i3 is opened and the furnace now is able to operate in itsnormal manner in res to the thermostat i5.

If desired, a suitable mechanical linkage or interlock of known form,between the main control valve and the pilot flame valve may beprovidedin order to prevent shutting the pilot valve until the mainvalve has been closed, and to prevent opening the latter until after thepilot valve opened.

In order to simplify the operation of turning on and oil the gas furnaceand to provide automatically for the increase or reduction in the pilotflame substantially simultaneously with the so time of turning on or of!respectively of the main gas supply, novel integral main and pilotcontrol means may be provided according to the embodiment shown in Fig.2 which comprises a valve 21 having a housing 28, an inlet 28a, and anoutlet so 2817. A rotatable valve member 29 is provided in said housinghaving a main channel 3| therethrough and a pilot fuel channel ll. Thelatter is preferably substantially perpendicular to channel 30 and is incommunication with pilot conduit 22 by means of a channel 32 which, forexample, is in direct connection with a pilot flame by-pass channel 33.Channel 22, however-[Indy be in direct connection with conduit 22. Theextremity of channel II which is in register with 7 channel 32 in Fig. 2is closed off entirely by housing 26 when rotatable valve member 29 isangularly shifted an amount sufficient to move said extremity out ofregister with channel 32.

By-pass channel 33 and channel 32 are preferably formed in the housing28. Channel 33 has an inlet at 33a, and an outlet 33b. By-pass inlet 33ais in communication with valve inlet 28a and is upstream relative torotatable valve member 23. Conduit 22 may be connected at 33b.

Suitable means are provided for manually rotating the valve member 29comprising a handle 34 which is preferably fixed directly to said valvemember.

In order to make fine adjustments of fuel fiow through the by-passchannel 33, a suitable bypass valve of, for example, the piston type isprovided at 35 which may be adjusted by angular movement of threadedmember 35a.

In operation, in the angular position of the rotatable valve member 29shown in Fig. 2, the fuel is able to flow freely from inlet 28a throughthe main channel 30 of valve member 29 to outlet 23b and thence to thefurnace via conduit 12. Fuel for the pilot flame reaches conduit 22 notonly through the by-pass 33 but also through the channels 3| and 32.Flow through the channels If and 32 is, of course, the main source ofpilot flame fuel. A. full pilot flame is thus sustained. If it isdesired to shut off the furnace, for example, for the summer, the handle34 is angularly shifted through 90 degrees in a clockwise direction.Thus in a single motion, and substantially simultaneously, the main fuelflow to the furnace and to the pilot flame are stopped. Only arestricted amount of gas may now flow to the pilot flame through by-pass33 in a quantity sufficient to produce a small but stable flame. Theintensity of the latter is, as above mentioned, insufficient to actuatethe safety thermostat I6 which promptly cools and opens the circuit l1,I3 thus causing the secondary valve l4 to shut off the main gas supplyto the burner. In this condition both the primary and secondary gascontrol valves (21 and II respectively) are closed thus providingadditional safety against gas leakage into the furnace or accidentaloperation thereof.

A reverse procedure is followedfor starting the furnace in operation.The handle 34 is reversed in movement to the position as shown in Fig.2. The full pilot flame is thus immediately produced without thenecessity for ignition by some separate means. In case the full pilotflame fails to come on for any reason, thermostat switch l6 will remainopen and valve It will remain closed.

The novel pilot flame control has been described in connection with agas furnace. However, it may be employed in any type of furnace burninga fuel which is adapted for ignition by a pilot light, for example, anoil burning furnace.

While the invention has been described with respect to certain preferredexamples which have given satisfactory results, it will be understood bythose skflled in the art after understanding the invention that variouschanges and modifications may be made without departing from the spiritand scope of the invention, and it is intended, therefore, in theappended claims, to cover all such changes and modifications.

' What is claimed as new and desired to be socured by Letters Patent is:

1. In apparatus of the class described, a min gas conduit, a gas burner,a primary control valve in said conduit, a secondary control valve insaid conduit, a pilot fuel conduit operatively associated with saidburner, a pilot flame burner connected to said pilot conduit, a pilotflame control valve in said pilot fuel conduit for controlling a fullpilot flame, by-pass means around said pilot flame control valvepermitting a restricted flow of gas for sustaining a small pilot flame,heatresponsive means adjacent said pilot flame burn er, and electricalmeans operatively connected to said heat responsive means and to saidsecondary control valve for controlling the latter by saidheat-responsive means, the latter being actuatable by said full pilotflame only.

2. Apparatus of the class described, comprising a fuel burner, a mainfuel conduit to the burner, fuel flow control means in said conduit, apilot conduit for feeding fuel to a pilot flame for said burner, a pilotflame burner connected to said pilot conduit, heat-responsive meansoperatively associated with said pilot flame burner and said fuel flowcontrol means, the heat responsive means being operatively associatedwith said fuel fiow control means by electrical means, and

. mechanism in the pilot conduit for adjusting the pilot flame to a fullsize and to a small size, said heat-responsive means being actuatable bya pilot flame of full size only.

3. Apparatus of the class described, comprising a fuel burner; a mainfuel conduit connected to said burner; primary fuel control means forsaid conduit; secondary fuel control means for said conduit; a pluralityof heat-responsive elements; electrical means for operativelyinterconnecting said elements and said secondary fuel control means; apilot tube having a pilot burner at which a pilot flame can burn forsaid first-mentioned burner. said pilot burner being positioned adjacentto one of said heat-responsive elements, the latter being aotuatable bya flame at said pilot burner; valve means in the pilot tube, said valvemeans when open permitting a full pilot flame fuel flow; and by-passconduit means around said valve means permitting a continuous smallpilot flame fuel flow, said heat-responsive element adjacent said pilotburner being actuatable by a full pilot flame only.

WOODS STOCKTON WALKER.

REFERENCES CITED The following references are of record in the file ofthis patent:

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